It concludes that the U.S. government can order the killing of American citizens if they are believed to be “senior operational leaders” of al-Qaida or “an associated force” -- even if there is no intelligence indicating they are engaged in an active plot to attack the U.S.

The debate, according to officials familiar with the deliberations, centers on whether the United States may take aim at only a handful of high-level leaders of militant groups who are personally linked to plots to attack the United States or whether it may also attack the thousands of low-level foot soldiers focused on parochial concerns: controlling the essentially ungoverned lands near the Gulf of Aden, which separates the countries.

The Defense Department view:

[I]f a group has aligned itself with Al Qaeda against Americans, the United States can take aim at any of its combatants, especially in a country that is unable or unwilling to suppress them.